Fiber optic device operating at two or more wavelengths

Abstract

A fiber optic device is used by fiber optic systems that operate with light at more than one wavelength. The device may be inserted anywhere within the fiber network. The fiber optic device permits the separation of the wavelengths so that an optical device can operate on that separated wavelength without operating on the other wavelength or wavelengths. The different wavelengths may then be recombined. In another embodiment, different wavelengths may be combined into a single fiber, with an optical device being disposed to operate on one of the wavelengths.

We claim:  
     
       1. A fiber optic device, comprising: 
       a first optical fiber optically coupled to transmit light at first and second wavelengths along a first optical path;  
       a wavelength separator disposed on the first optical path and adapted to direct light at the first wavelength along a second optical path and light at the second wavelength along a third optical path different from the second optical path;  
       a wavelength combiner optically coupled to combine light propagating along the second and third optical paths into a fourth optical path;  
       a second optical fiber optically coupled to the fourth optical path;  
       a first optical device disposed along the second optical path, between the wavelength separator and the wavelength combiner to operate on light at the first wavelength; and  
       a first collimating unit disposed to couple light between the first optical fiber and the first optical path, and to couple light between the second optical fiber and the fourth optical path.  
     
     
       2. A device as recited in  claim 1 , further comprising a second optical device disposed along the third optical path, between the wavelength separator and the wavelength combiner to operate on light at the second wavelength. 
     
     
       3. A device as recited in  claim 1 , further comprising a housing containing the wavelength separator, the wavelength combiner and the first optical device. 
     
     
       4. A device as recited in  claim 1 , further comprising a parallelizing optic disposed between the collimating unit and both the wavelength separator and wavelength combiner. 
     
     
       5. A device as recited in  claim 1 , wherein the wavelength separator is a dichroic mirror. 
     
     
       6. A device as recited in  claim 1 , wherein the wavelength combiner is a dichroic mirror. 
     
     
       7. A device as recited in  claim 1 , wherein the wavelength separator is a polarization separator. 
     
     
       8. A device as recited in  claim 1 , wherein the first optical device is a filter. 
     
     
       9. A device as recited in  claim 1 , wherein the first optical device is an optical switch. 
     
     
       10. A device as recited in  claim 1 , wherein the first optical device is an optical modulator. 
     
     
       11. A device as recited in  claim 1 , wherein the first optical device is a first optical circulator. 
     
     
       12. A device as recited in  claim 11 , further comprising a third optical fiber, wherein light propagating through the first optical circulator from the wavelength combiner is directed along a fifth optical path, different from the second optical path, to the wavelength separator, and along a sixth optical path from the wavelength separator to the third optical fiber. 
     
     
       13. A device as recited in  claim 12 , further comprising a second optical circulator disposed in the third optical path, wherein light propagating through the second optical circulator from the wavelength combiner is directed along a seventh optical path, different from the third optical path, to the wavelength separator, and is combined with light propagating along the fifth optical path to propagate along the sixth optical path to the third optical fiber. 
     
     
       14. A system as recited in  claim 1 , wherein the first wavelength is 1.55 μm. 
     
     
       15. A system as recited in  claim 1 , wherein the difference between the first and second wavelengths is at least 20 nm. 
     
     
       16. A fiber optic device, comprising: 
       wavelength splitting means for splitting a light beam into a first light beam containing light at a first wavelength and a second light beam containing light at a second wavelength, the first and second beams respectively propagating along first and second beam paths;  
       a first optical device disposed on the first beam path to operate on the first light beam;  
       wavelength combining means for combining light propagating in the first direction along the first beam path, and light propagating in the first direction along the second beam path into a single output beam; and  
       light collimating and focusing means for commonly collimating the light beam incident on the wavelength splitting means and focusing the single output beam.  
     
     
       17. A fiber optic device, comprising: 
       first and second optical fibers optically coupled via first and second optical paths respectively to a wavelength combiner, light at a first wavelength from the first optical fiber being combined with light at a second wavelength from the second fiber at the wavelength combiner to form a combined output beam;  
       a third optical fiber coupled via a third optical path to receive the combined output beam from the wavelength combiner;  
       a first optical device positioned on the first optical path and between the first optical fiber and the wavelength combiner; and  
       a collimating unit disposed on the first optical path and on the second optical path to collimate light entering the device from the first and second fibers.  
     
     
       18. A device as recited in  claim 17 , further comprising a second optical device disposed on the second optical path between the second optical fiber and the wavelength combiner. 
     
     
       19. A device as recited in  claim 17 , further comprising a housing containing the wavelength combiner and the first optical device. 
     
     
       20. A device as recited in  claim 17 , wherein the wavelength combiner includes a dichroic reflector. 
     
     
       21. A device as recited in  claim 17 , wherein the wavelength separator is a polarization separator. 
     
     
       22. A device as recited in  claim 17 , wherein the first optical device is an optical modulator. 
     
     
       23. A device as recited in  claim 17 , wherein the first optical device is an optical filter. 
     
     
       24. A device as recited in  claim 17 , further comprising a parallelizing optic disposed between the collimating unit and the wavelength combiner. 
     
     
       25. A device as recited in  claim 17 , further comprising a first optical transmitter coupled to the first optical fiber, an optical receiver coupled through an external fiber optic system to the third optical fiber and a second light source coupled to second optical fiber. 
     
     
       26. A device as recited in  claim 17 , further comprising a second collimating unit disposed on the third optical path between the wavelength combiner and the third optical fiber. 
     
     
       27. A fiber optic device, comprising: 
       a first optical fiber optically coupled via a first optical path to a wavelength separator to transmit light to the wavelength separator, the wavelength separator arranged to separate light received from the first optical fiber into components at first and second wavelengths;  
       a second optical fiber coupled via a second optical path to the wavelength separator to receive light at the first wavelength;  
       a third optical fiber coupled via a third optical path to the wavelength separator to receive light at the second wavelength;  
       a first optical device positioned on the second optical path and between the second optical fiber and the wavelength separator; and  
       a collimating unit disposed to couple light from the second optical path to the second optical fiber and to couple light from the third optical path to the third optical fiber.  
     
     
       28. A device as recited in  claim 27 , further comprising a second optical device disposed on the third optical path between the wavelength separator and the third optical fiber. 
     
     
       29. A device as recited in  claim 27 , further comprising a housing containing the wavelength separator and the first optical device. 
     
     
       30. A device as recited in  claim 27 , wherein the wavelength separator includes a dichroic reflector. 
     
     
       31. A device as recited in  claim 27 , wherein the wavelength separator is a polarization separator. 
     
     
       32. A device as recited in  claim 27 , wherein the first optical device is an optical modulator. 
     
     
       33. A device as recited in  claim 27 , wherein the first optical device is an optical filter. 
     
     
       34. A device as recited in  claim 27 , a parallelizing optic disposed between the collimating unit and both the second and third optical fibers. 
     
     
       35. A device as recited in  claim 27 , further comprising a second collimating unit disposed on the first, optical path between the first optical fiber and the wavelength separator.